The Behavioral Sciences Core has two components: shared resource, or service, and behavioral science research. The first centralizes resources to support developed interventions: (1) Chemoprevention of Skin Cancer by Retinoids; (2) Actinic Keratosis Phase I and II trials; (2) Beta-carotene clinical pharmacology study; (3) Beta-carotene and Vitamin E clinical pharmacology study; and (4) Phase II oral leukoplakia trials with behavioral components. The aims of the shared resource component are: (1) adherence/compliance enhancement for all trials named above; (2) Behavioral science support for applicable developmental studies; and (3) Consultation with other Cores and projects. Hypotheses for the research component are: (1) the adherence enhancement strategy per the Health Behavior in Cancer Prevention Model predicts short and long term adherence in cancer prevention and control trial samples; (2) Health Behavior Profiles differ for good, marginal and poor adherers; (3) The adherence enhancement strategy is associated with good adherence. The correlational descriptive design for H3 is a prospective case control study of a subsample of poor and marginal compliers with matched good complier controls in trials with n>-100. The case control study sample estimate is 84 based on current study levels of marginal/poor compliers. DFMO/Retin-A (n=120) trial subjects are 40-80 year old men. Subjects in the Phase II oral leukoplakia (n=143) trial are also approximately 40-80 years old men and women. Other trials have less than 100 subjects. Analyses for H1 include OLS and LOGIT, graphic analysis for H2 and H3, and conditional LOGIT for H3. Study outcomes include description and explanation of factors in adherence failure, and a test of the effectiveness of the general and individualized compliance interventions.